Metallurgical and technological investigation on Augustean auxiliary coins from Thraco-Moesia

Abstract

The impressive amount of Augustean coins coming from the Thraco-Moesia area (classified in numismatic terms as "Limesfalsa"), raises some juridical and technical questions as to who were the issuing authorities and to the production techniques involved. In the present investigation a representative sampling of such coins, based on metallographic and chemical analysis, was compared on the basis of metallographic and chemical analysis to some regular coins coming from the mint of Rome. The main results can be summarized as follows: The regular Augustaan Asses are composed of almost pure Cu, with a fine recrystallized structure, whereas a part of the "auxiliary" samples have a lower Cu content, with varying amounts of Pb and a coarser dendritic grain structure. The Dupondii are made of brass: The "auxiliary" samples have usually a lower weight and Zn content than the regular ones, and sometimes an irregular shape. This data may not only confirm the theory of a partly de-centralized issuing of the base metal coins, but also the hypothesis that the primary brass production occurred under the control of the central mint.